Cain: Apparently indestructible and possibly immortal; diabolical cunning; bears the "Mark of Cain" which protects him from all harmAbel: Possibly immortal and apparently indestructible; Resurrects from any fatal wound inflicted by Cain

Cain, "the Able Care-Taker," created by Bob Haney, Jack Sparling and Joe Orlando, first appeared in The House of Mystery #175 (July–August 1968), modeled on writer Len Wein, who was new to the field.[2] A photograph of Wein as Cain can be found in Elvira's House of Mystery #4.

Abel, created by Mark Hanerfeld, Bill Draut, and Joe Orlando, first appeared in DC Special #4 (July–September 1969), and began hosting The House of Secrets with #81 (August–September 1969). Hanerfeld was the model for Abel, and he also appeared in a photograph in Elvira's House of Mystery #4.[3]

On the letters page of Weird Mystery Tales #3 (November 1972), Destiny stated that Cain, Abel, and Eve were not the same characters as their biblical counterparts, whom Destiny said he found much more pleasant. Cain, Eve, and to a lesser extent, Abel, subsequently taunt Destiny for being dull.

House of Mystery was canceled in 1983. The final issue showed Cain in front of the House for sale, with his bags packed, and Gregory, his pet gargoyle, behind him. The cover of Vertigo's mostly-reprintWelcome Back to the House of Mystery showed him returning with Abel and Gregory. The House of Secrets and The Witching Hour were eventually merged with The Unexpected and canceled around the same time. Cain then became a supporting character in Blue Devil, with Abel and Gregory making occasional appearances as well.

Cain told tales of various people who boarded at the House of Mystery. Abel stammeringly took abuse from both Cain and the House of Secrets itself, and had an "imaginary" (it was always rendered in quotes) girlfriend named Goldie, who berated him too.[1] In the early issues, Abel told the stories directly to Goldie, although he always appeared to be alone. He said she was a ghost.

Cain is a thin, long-limbed man with an angular, drawn face, glasses, a tufty beard, and hair drawn into two points above his ears. Cain is often mean to Abel, but he is jovial and a friendly storyteller to children and did everything he could to help Superman when the need once arose; however, he has no qualms trapping innocent people inside his television set[4] and he was once employed by a vicious mink furrier.[5] Abel is a nervous, stammering, kind-hearted man. Abel also has a tufty beard and hair that comes to points above his ears, though his hair is black rather than brown. He is shorter and fatter than Cain, with a more open face. It is eventually stated (in Sandman #40) that the only time he doesn't stutter is when he is telling a story, and this was characteristic of his earlier appearances. Cain owns a large green draconian gargoyle named Gregory, who first appeared (as a baby) in House of Mystery #175, apparently the offspring of enchanted sculptures who come to the house for a French sculptor who murdered the artist who designed them. Gregory grew to maturity over the course of the series and continued to appear in Sandman stories. Gregory ate the Earth-1 counterparts of writer Paul Kupperberg and editor Jack C. Harris.[6] Cain also used to have a black cat named Oskar, who did not get along with Gregory.

Abel moved in with Cain in the House of Mystery shortly before DC Special #4, which Cain states is a temporary situation until the House of Secrets is transported (which occurred in House of Secrets #81, which appeared one month later). Their ages are vague, but Abel presents a story that he claims to have heard from Cain, who scared him with it as a child in 1957.[7] The story in question originally appeared in Tales of the Unexpected #17 (September 1957).

In the final issue of The House of Mystery, Karen Berger, whom Cain first met in issue #292—the first issue she edited for DC—arrives as an unexpected guest at Cain's birthday party, takes him through a secret door that leads to the DC offices, and tells him that his series has been canceled and that he is too old-fashioned. The House is torn down, and Cain metafictionally analyzes his own existence as a character in a comic book.[8]

In 1985, the characters were revived by writer Alan Moore, who introduced them into his Swamp Thing series in the issue #33, retelling the Swamp Thing's original origin story as depicted in a 1971 issue of House of Secrets. Cain kills Abel for revealing a secret (the difference between a mystery and a secret is that a mystery can be shared and still remains a mystery) and declares to Abby Holland, "I invented murder!" In Blue Devil #20 (January 1986), Cain is the caretaker of "The House of Weirdness" until Blue Devil moves in, and discovers that Abel is there, too. He states that the California mansion is owned by "a publishing company back East".

During the Crisis, although not mentioned in that series, Elvira stumbled onto the House of Mystery, which charged her to find Cain, who had disappeared. Metropolis can be seen through a window in the garage of the House of Weirdness.[9] Cain and Blue Devil can be seen peering at Elvira in Elvira's House of Mystery.[10] Cain and Abel reappeared in Swamp Thing #49-50, where they acted as observers and commentators on a fierce battle in Hell.

They were depicted together in Abel's first appearance, and they parted to their respective Houses at the end of the story, the House of Secrets having been recently moved, with Cain promising things not to go the way they happened before. Although Cain would abuse Abel, he was not shown killing him until Swamp Thing vol. 2 #33. More often than not, though, they did not appear together, and Cain directed more of his taunts at the reader, while Abel tried to reassure Goldie or the reader. Indeed, in The House of Mystery #257 (April 1978), an asylum escapee, "Killer" Cowan, kills six people on Christmas Eve, storming into the House of Mystery wearing a Santa Claus suit and demands Cain to keep him occupied by entertaining him with stories. Cain protests that he does not want to entertain someone who ruins all that the holiday stands for. Abel is said to be a voyeur in Secrets of Sinister House #14, and shown to be such in The Sandman #60.

In Gaiman's Sandman universe, it is implied by dialogue between Lucifer and Cain (who had been sent by Dream as a messenger due to his invulnerability) that the biblical Cain and Abel came to live in the Dreaming at Dream's invitation. To support this, Lucifer quotes the verse in the Bible which says that Cain was sent to live in the Land of Nod. This could be a post-Crisisretcon, however, as Destiny claimed in Weird Mystery Tales #3 that they were not the same as the Biblical Cain and Abel. The nature of reality in the Dreaming is often multiple and when Cain, Abel, and Eve are telling young Daniel Hall three stories, Cain objects to Abel's "Lil' Endless" style retelling of their origin claiming that "... they (the Endless) didn't even look remotely human, none of us did!" Abel later responds to Matthew the Raven's query about whether they are their biblical namesakes or not by stating; "...oh, none of this happened on Earth..." before being interrupted by Cain. Eve also states that she is not Cain's mother to which Cain replies, "You're everyone's mother."[11] This sequence of events would seem to indicate that rather than being the actual literal beings Cain, Abel, and Eve the Dreaming's incarnation of them are closer to their archetypal roles of first murderer, first victim, and first mother. This is supported by several incidents when Cain or Abel have identified themselves as such and claimed that their cycle of murder and resurrection is punishment for their role in the first murder.[12] This would also allow Joe Kubert's DC Comics adaptation of the Cain and Abel story from the Bible, in which he ignored their "Mystery" likenesses, to fit neatly into canon.[13]

Cain frequently kills Abel in a kind of macabre form of obsessive-compulsive disorder, re-enacting the first murder.[1] In the Dreaming, Abel's death is impermanent, and he seems to recover after a few hours. Cain seems unable to control his frequent murders of Abel, and occasionally expresses remorse over them; there is a genuine bond between the two, beneath the surface contempt. Abel remains dedicated to Cain, and frequently dreams of a more harmonious relationship between the two.

In turn, in the graphic novel The Sandman: The Wake, Cain is so distraught when Abel is murdered permanently by The Kindly Ones, he sinks into a rambling mess when asking the new Dream to restore him. In preparation for the funeral services for the deceased Dream, Cain's anger boils over yet again when Abel reveals a secret, but he is calmed by a reprimand and restrained from murdering Abel. He displays a contract, renewed in 1989 (the year The Sandman began) that states that only he is allowed to kill Abel, because Abel can resurrect only when Cain kills him.

In the first appearance of the characters in Sandman, issue #2, Cain gives Abel an egg that soon hatches into another gargoyle, a small golden one. Abel is delighted and names the gargoyle "Irving," but Cain forcefully insists that the names of gargoyles must always begin with a "G." When Abel resists, Cain murders him, and after Abel revives he renames the gargoyle "Goldie," after a friend of his who "went away."

The main function of Cain and Abel throughout The Sandman is as comic relief. However, the two play significant (though not key) roles at several points in the series; it is they who take Morpheus in until his strength is restored following his 72-year-long imprisonment. In the fourth story arc, Season of Mists, Cain is sent to Hell to give a message to Lucifer because the Mark of Cain protects him. Those who would harm Cain would have the full wrath of God visited upon them. Lucifer merely finds this funny, since he is already in Hell.

Recently, both Cain and Abel have appeared in the new House of Mystery title. Abel appeared in the missing House of Mystery with Goldie, claiming to be on a secret mission to retrieve the various nightmares that were still in the house when it vanished. Meanwhile, Cain, under the guise of a mysterious coachman, plotted with various groups to retake the House of Mystery, which he saw as his rightful property. Eventually, Cain was able to broker a deal to become the co-manager of the House of Mystery's current incarnation as a bar, and both he and Abel have become regular members of the series' cast.